The primary function of this group has been to apply the principles of pharmacokinetics to questions of relevance to the treatment of cancer. Studies completed or active include: 1. Regional drug delivery, including intraarterial, intraperitoneal, and intraventricular routes of administration -- Pediatric, Surgery, and Surgical Neurology Branches. 2. Halogenated pyrimidine radiosensitizers -- Radiation Oncology Branch 3. Phase I trials of new agents (Tiazofuran, Dihydroazacytidene, Carboplatinum, Spiromustine) -- Medicine and Surgical Neuorology Branches 4. Pharmacokinetic evaluation of established agents -- Adriamycin, 6-mercaptopurine, cisplatin -- Medicine and Pediatric Branches In addition to direct clinical pharmacokinetic projects, this group has ongoing projects on the relationship between preclinical and human pharmacokinetics studies. Both experimental studies (rodents) and theoretical aspects are included. Similarly, this group is interested in the relationships between in vitro chemosensitivity and in vivo response. More detailed pharmacokinetic modeling has been jointly developed in collaboration with the Biomedical Engineering and Instrumentation Branch, DRS/NIH.